In a Bain Marie melt ½ pound dark chocolate and ¼ pound unsalted butter. Meanwhile, separate 5 egg yolks and whites. Add 5 oz. sugar to the yolks and mix for at least 60 seconds until sugar is dissolved and mixture is ribbon-like. Beat egg whites until soft peaks form. Take a cake pan (10" round by 2" high), butter the pan heavily so cake will not stick and place in freezer for 15 minutes. Butter again and place in freezer. Combine chocolate mixture and yolk mixture. Fold in egg whites gently. Remove pan from freezer and place mixture in pan.

In a preheated 300° oven, cook for 70 minutes. Remove from oven and cool for 15 minutes at room temperature. Invert cake onto a plate and serve with fresh whipped cream, chocolate shavings.